diff --git a/images/apple/DCGR-RGB.PO b/images/apple/DCGR-RGB.PO
index 04ae1e14..fab24178 100755
Binary files a/images/apple/DCGR-RGB.PO and b/images/apple/DCGR-RGB.PO differ
diff --git a/src/dhgr.tk/utils/dhgrrgb.pla b/src/dhgr.tk/utils/dhgrrgb.pla
index 603b1a21..20130e8d 100644
--- a/src/dhgr.tk/utils/dhgrrgb.pla
+++ b/src/dhgr.tk/utils/dhgrrgb.pla
@@ -55,82 +55,102 @@ def dist(x1, y1, z1, x2, y2, z2)#2
   return xx:[0], xx:[1]
 end
 
-def rgbPix(r, g, b, nr, ng, nb, x, y)#0
+def rgbPix(r0, g0, b0, r1, g1, b1, r2, g2, b2, x)#1
   var errptr
-  var pr, pg, pb
-  var lr, lg, lb
+  var pr1, pg1, pb1
+  var pr2, pg2, pb2
+  var pr3, pg3, pb3
+  var lr0, lg0, lb0
+  var lr1, lg1, lb1
+  var lr2, lg2, lb2
+  var er, eg, eb
   var cr, cg, cb, cx
   byte i
-  res[t_i32] pd, cd, nd
+  res[t_i32] pd, d0, d1, d2
 
   // Error propogation
   errptr = rgbErr + x * 3 * 2
+  // Previous 3/4 chroma cycle
+  i = ((x - 1) & 3) * 3
+  pr1 = ntscCycle[i+RED]
+  pg1 = ntscCycle[i+GRN]
+  pb1 = ntscCycle[i+BLU]
+  i = ((x - 2) & 3) * 3
+  pr2 = pr1 + ntscCycle[i+RED]
+  pg2 = pg1 + ntscCycle[i+GRN]
+  pb2 = pb1 + ntscCycle[i+BLU]
+  i = ((x - 3) & 3) * 3
+  pr3 = pr2 + ntscCycle[i+RED]
+  pg3 = pg2 + ntscCycle[i+GRN]
+  pb3 = pb2 + ntscCycle[i+BLU]
+  // Current chroma cycle
+  i = (x & 3) * 3
+  cr = pr3 + ntscChroma[i+RED]
+  cg = pg3 + ntscChroma[i+GRN]
+  cb = pb3 + ntscChroma[i+BLU]
   if errDiv
-    r = r + errptr=>[RED] / errDiv
-    g = g + errptr=>[GRN] / errDiv
-    b = b + errptr=>[BLU] / errDiv
+    r0 = r0 + errptr=>[RED] / errDiv
+    g0 = g0 + errptr=>[GRN] / errDiv
+    b0 = b0 + errptr=>[BLU] / errDiv
   fin
-  pr = 0
-  pg = 0
-  pb = 0
-  // Previous 3/4 chroma cycle
-  for cx = x - 1 downto x - 3
-    i  = (cx & 3) * 3
-    pr = pr + ntscCycle[i+RED]
-    pg = pg + ntscCycle[i+GRN]
-    pb = pb + ntscCycle[i+BLU]
-  next
-  pd:[0], pd:[1] = dist(r, g, b, pr, pg, pb)
   // Look ahead in chroma cycle for possible better match for next RGB pixel
   i  = ((x + 1) & 3) * 3
-  lr = pr - ntscCycle[i+RED] + ntscChroma[i+RED]
-  lg = pg - ntscCycle[i+GRN] + ntscChroma[i+GRN]
-  lb = pb - ntscCycle[i+BLU] + ntscChroma[i+BLU]
+  lr1 = pr2 + ntscChroma[i+RED]
+  lg1 = pg2 + ntscChroma[i+GRN]
+  lb1 = pb2 + ntscChroma[i+BLU]
+  if errDiv
+    r1 = r1 + (errptr=>[3+RED] + r0 - lr1) / errDiv
+    g1 = g1 + (errptr=>[3+GRN] + g0 - lg1) / errDiv
+    b1 = b1 + (errptr=>[3+BLU] + b0 - lb1) / errDiv
+  fin
+  // Look ahead in chroma cycle for possible better match for after next RGB pixel
+  i  = ((x + 2) & 3) * 3
+  lr2 = pr1 + ntscChroma[i+RED]
+  lg2 = pg1 + ntscChroma[i+GRN]
+  lb2 = pb1 + ntscChroma[i+BLU]
   if errDiv
-    nr = nr + (errptr=>[3+RED] + r - lr) / errDiv
-    ng = ng + (errptr=>[3+GRN] + g - lg) / errDiv
-    nb = nb + (errptr=>[3+BLU] + b - lb) / errDiv
+    r2 = r2 + (errptr=>[3+RED] + r1 - lr2) / errDiv
+    g2 = g2 + (errptr=>[3+GRN] + g1 - lg2) / errDiv
+    b2 = b2 + (errptr=>[3+BLU] + b1 - lb2) / errDiv
   fin
-  nd:[0], nd:[1] = dist(nr, ng, nb, lr, lg, lb)
-  // Current 1/4 chroma color
-  i  = (x & 3) * 3
-  cr = pr + ntscChroma[i+RED]
-  cg = pg + ntscChroma[i+GRN]
-  cb = pb + ntscChroma[i+BLU]
-  cd:[0], cd:[1] = dist(r, g, b, cr, cg, cb)
-  load32(@cd)
-  if islt32(@pd) and islt32(@nd)
+  // Calc match if current pixel is zero
+  pd:[0], pd:[1] = dist(r0, g0, b0, pr3, pg3, pb3)
+  // Calc match if next pixel is one
+  d2:[0], d2:[1] = dist(r2, g2, b2, lr2, lg2, lb2)
+  // Calc match if after next pixel is one
+  d1:[0], d1:[1] = dist(r1, g1, b1, lr1, lg1, lb1)
+  // Calc match if current pixel is one
+  d0:[0], d0:[1] = dist(r0, g0, b0, cr, cg, cb)
+  i = (x & 3) * 3
+  load32(@d0)
+  if islt32(@pd) and islt32(@d1) and islt32(@d2)
     // RGB better matched with current 1/4 chroma color
-    nr = r - cr
-    ng = g - cg
-    nb = b - cb
+    er = r0 - cr
+    eg = g0 - cg
+    eb = b0 - cb
     ntscCycle[i+RED] = ntscChroma[i+RED]
     ntscCycle[i+GRN] = ntscChroma[i+GRN]
     ntscCycle[i+BLU] = ntscChroma[i+BLU]
-    dhgrSet(x, y)
+    i = 1
   else
     // RGB closer to black
-    nr = r - pr
-    ng = g - pg
-    nb = b - pb
+    er = r0 - pr3
+    eg = g0 - pg3
+    eb = b0 - pb3
     ntscCycle[i+RED] = 0
     ntscCycle[i+GRN] = 0
     ntscCycle[i+BLU] = 0
+    i = 0
   fin
   // Propogate error down and forward
-  errptr=>[RED] = nr
-  errptr=>[GRN] = ng
-  errptr=>[BLU] = nb
+  errptr=>[RED] = er
+  errptr=>[GRN] = eg
+  errptr=>[BLU] = eb
   errptr = errptr + 6
-  errptr=>[RED] = nr + errptr=>[RED]
-  errptr=>[GRN] = ng + errptr=>[GRN]
-  errptr=>[BLU] = nb + errptr=>[BLU]
-  // Map dark grey to light grey
-  if (x & 3) == 3 and dcgrGetPixel(x >> 2, y) == 5
-    dhgrOp(OP_SRC)
-    dcgrColor(10)
-    dcgrPixel(x >> 2, y)
-  fin
+  errptr=>[RED] = er + errptr=>[RED]
+  errptr=>[GRN] = eg + errptr=>[GRN]
+  errptr=>[BLU] = eb + errptr=>[BLU]
+  return i
 end
 
 def rgbInit#0
@@ -151,8 +171,8 @@ def rgbInit#0
   fin
   dhgrMode(DHGR_COLOR_MODE)
   // Init error propogation array
-  rgbErr = heapalloc(561 * 3 * 2)
-  memset(rgberr, 0, 561 * 3 * 2)
+  rgbErr = heapalloc(563 * 3 * 2)
+  memset(rgberr, 0, 563 * 3 * 2)
   rgberr=>[RED] = -1
   rgberr=>[GRN] = -1
   rgberr=>[BLU] = -1
@@ -164,30 +184,42 @@ def rgbExit#0
 end
 
 def rgbImportExport(rgbfile, dhgrfile)#0
-  byte refnum, r, g, b, nxtr, nxtg, nxtb
+  byte refnum, r0, g0, b0, r1, g1, b1, r2, g2, b2
   var i, j
   var rgbScanline, rgbptr
 
   refnum = fileio:open(rgbfile)
   if refnum
-    rgbScanline = heapalloc(560 * 3)
+    rgbScanline = heapalloc(563 * 3)
+    memset(rgbScanline, 0, 563 * 3)
     if rgbScanline
       rgbInit
       for j = 0 to 191
         fileio:read(refnum, rgbScanline,  560 * 3)
         rgbptr = rgbScanline
-        nxtr = gamma[rgbptr->RED]
-        nxtg = gamma[rgbptr->GRN]
-        nxtb = gamma[rgbptr->BLU]
+        r1 = gamma[rgbptr->RED]
+        g1 = gamma[rgbptr->GRN]
+        b1 = gamma[rgbptr->BLU]
+        rgbptr = rgbptr + 3
+        r2 = gamma[rgbptr->RED]
+        g2 = gamma[rgbptr->GRN]
+        b2 = gamma[rgbptr->BLU]
         for i = 0 to 559
-          r = nxtr
-          g = nxtg
-          b = nxtb
+          r0, g0, b0 = r1, g1, b1
+          r1, g1, b1 = r2, g2, b2
           rgbptr = rgbptr + 3
-          nxtr = gamma[rgbptr->RED]
-          nxtg = gamma[rgbptr->GRN]
-          nxtb = gamma[rgbptr->BLU]
-          rgbPix(r, g, b, nxtr, nxtg, nxtb, i, j)
+          r2 = gamma[rgbptr->RED]
+          g2 = gamma[rgbptr->GRN]
+          b2 = gamma[rgbptr->BLU]
+          if rgbPix(r0, g0, b0, r1, g1, b1, r2, g2, b2, i)
+            dhgrSet(i, j)
+          fin
+          // Map dark grey to light grey
+          if (i & 3) == 3 and dcgrGetPixel(i >> 2, j) == 5
+             dhgrOp(OP_SRC)
+             dcgrColor(10)
+             dcgrPixel(i >> 2, j)
+          fin
         next
         if ^$C000 == $83
           break